Centrifugal casting apparatus



Jan. 28,1947. 7 J. J. NOLAN, J 2,414,890

CENTRIFUGAL CASTING APPARATUS Filed Dec. 15', 194::

INVENTOR.

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,yrraewe-Y Patented as. 28, 1947 2,414,890 CENTRIFUGAL CASTING A PPARA'IUS John J. Nolan, Jn, New York, N. Y., assignmto The Central Foundry Company, New York, N. Y., a corporation of Maine Application December- 15, 1943, Serial No. 514,369

4 Claims. 1

The inventionrelates to apparatus for the centrifugal casting of iron pipe and the like; and,

more particularly, to improvements in two-part molds and in the means for feeding metal to the molds.

In my copending application, Serial Number 497,223, now matured into Patent No. 2,378,723, dated Jun 19, 1945, I have described an improved method of making cast iron pipe in permanent molds, such as a two-part iron mold. The present invention relates to improvements in the means for feeding metal into the mold, which improvements are particularly useful in the'practice of that method, and which are also useful in the centrifugal casting of iron pipe by other methods known to the art.

In the practice of the method described in my copending application supra, a type of mold is selected which permits rapid removal of the casting so that such removal can be effected at the very moment that the casting has solidified sufficiently to hold its form. One of the features of my present invention is the provision of im-.

provements in the means for feeding metal to the known types of two-part molds which facilitate rapid removal of the casting andits attached sprue and thus increase their usefulness in the practice of the method referred to.

it is an objectof my invention to provide, in

conjunction witha mold adapted for rotation about a substantially horizontal axis, a metalfeeding element having improved means for imparting a swirling motion to the metal as it is delivered to the rotating mold, designed to produce'rapid, smooth and less turbulent flow of the metal, and to lessen erosion of the mold.

Another object is to provide a metal-feeding element of the class described which can be directly attached to a mold and which will permit ready removal of the casting and sprue without detachment of the feeding element from the of one of the two members which go to make up the metal-feeding device.

Fig. 3 is an end elevationalview of the complete metal-feeding device. The upper half of this view is a third quadrant projection of Fig. 2,

the projection having been rotated through a 90 angle in a counterclockwise direction.

Referringto Fig. 1, I have shown a'two-part mold 4 comprising a cope half 5 and drag half 6 of a type designed for making cast iron pipe. The mold is preferably made of iron or steel. It is mounted for rotation about a substantially horizontal axis as by means of supporting it on flanged friction rollers, one of which is indicated at 1, engaging flanges on the mold, one of which is indicated at B. The present invention is not concerned with the particular means for supporting or rotating the mold, and any means known to the art for these purposes may be employed.

The mold will have a cylindrical inner surface 9 and may have flange or hub-forming cavities It at either end, or at both ends, as may be desired.

In accordance with my invention, a metal feeding element l I is fixed to one end of the mold for rotation therewith. This feeding element is divided into two parts, designated [2 and [3, substantially alongthe parting line H of the mold. The main body of the feeding element is tubular in form and near its inner end it is provided with an annular flange I5 which preferably is formed as an integral part of the device. Thus one-half of the'flange is formed on the part I2 and the other half on the part l3, together forming the complete flange as shown in Fig. 3. The flange is provided witha series of openings IE to receiv thebolts ll for securing the feeding element to the end of the mold. A portion Ill of the feeding element may be arranged to project into the mold for a short distance, this portion being joined to the flange l5 by a bevelled portion it which is arranged to'engage a complementary bevelled surface on the inside edge of the mold end.

The outer surface 20 of the feedin element H preferably is tapered so that a, clamping ring 2| may be-wedged over it to hold the two part l2 and I3 tightly together. The feeding device is adapted to receive the end of a pouring trough 22 which is arranged to project into the end of the device to deliver the charge of metal.

The feeding element is rovided with means for imparting a swirling motion to the metal delivered thereto during rotation of the mold and one of the features of my invention resides in the particular arrangement and form of the means of accomplishing this purpose, which means com-- prises the pair of inclined ribs 23 fixed to the inner surface of the feeding element. With particular reference to Figs. 2 and 3, it will be observed that these ribs are inclined with respect to the rotation axis of the mold. The ribs preferably are of helical form, and the leading end of each rib is higher (radially of the feeding element I I) than the trailing end. Thus,-in my preferred construction, the height of the rib progressively in creases toward its leading end, as shown at 24 (Fig. 3). There is one rib on the part I! and one rib on the part I! of the device, and each rib has a sloping leading face 25 and an upright trailing face 28.. I have found that best results are obtained when theleading face 25 are inclined at an angle of about 45 to the axis of the feeding element, although I do not limit myself to this angle which is somewhat dependent upon the speed of rotation and the rate of feed desired. I have found that the particular form and arrangement of the ribs which I have described is especially advantageous in the centrifugal casting of iron pipe in permanent molds at speeds of from 800 to 800 R. P. M. in accordance with the method more particularly described in my copending application Serial Number 497,223 supra. The metal discharging from the trough 22 i picked up by the trailing ends of the ribs 23 and is carried forward along the progressively widening sloping leading face of the ribs which exert a progressively increasing rotary propulsion on the metal, causing it to swirl faster and faster until it reaches the point of discharge where it is propelled into the mold in a relatively mooth stream with the least amount of turbulence. The metal runs in a wave to the far end of the mold and fills the cavities at that end which form the hub or lugs, and then the returning wave fills the hub or lug cavities at the entering end.

The pitch of the helical ribs 23 maybe varied somewhat in accordance with the speed of rotation of the mold and rate of introduction of the metal as will be understood by one who is familiar with the art of centrifugal casting.' The features which I have particularly described are important regardless of pitch.

The ribs may be formed separately from the body of the device and attached thereto a by means of weldingv or they may be formed integrally therewith. While the body of the feeding element is generally of tubular or cylindrical form,

to holdits form, permitting removal of the casting and the attached sprue without detachment of the feeding element from the mold. This is made possible partly by the fact that the feeding element is divided into two parts along the parting line of the mold, and partly by reason of the form of the ribs. A study of Fig. 2 will reveal that not only is the sloping leading face 25 of the ribs of value from the standpoint of producing a smooth metal flow, but also from the-standpoint of permitting withdrawal ofone part of the feeding element from the sprue solidified therein. After the mold has been unlocked and the ring 2| removed from the member ll preparatory to removal of the casting, the upper part of the mold and the upper part 12 of the feeding element can be lifted free as a unit. leaving the casting and attached sprue in the other half of the mold and feeding element. Thereafter the casting and sprue can be knocked free from the lower half and removed in any convenient manner as by means of a crane hoist,

The terms and expressions which I have employed are used in a descriptive and not a limiting sense, and I have no intention of excluding such equivalents of the invention described, or of portions thereof. as fall within the purview of the claims. I v

I claim:

1. In apparatus for the centrifugal casting of iron pipe and the like, a mold adapted for rotation about a. substantially horizontal axis, and a metalfeeding element fixed to one end of the mold for rotation therewith, said mold and feeding element being divided into two parts along a substantially central parting line lengthwise of the mold, each part of the feeding element having a helical rib on its inner surface, said ribs having sloping leading faces.

2. In apparatus for the centrifugal casting of iron pipe and the like, a mold adapted for rotation about a substantially horizontal axis, and a metalfeedingelement fixed to one end of the mold for rotation therewith, said feeding element having a helical rib on its inner surface, said rib having a sloping leading face.

3. In apparatus for the centrifugal casting of iron pipe and the like, a mold, and a rotary feeding element of hollow cylindrical form fixed thereto, said mold and feeding element being formed in two parts separable along an axial parting ine, each part having on its inner surface a helical rib the height of which progressively increases toward its leading end, and each rib having a, sloping leading face.

4. In apparatus for the centrifugal casting of iron pipe and thelike, a mold, and a. rotary feeding element of hollow cylindrical form fixed'thereto, said mold and feeding element being formed in two parts separable along an axial parting .lin'e, each part having on its inner surface a hell- JOHN J, NOLAN, JR. 

